Euxinic

Pertaining to an environment of restricted circulation and stagnant or anaerobic conditions, such as a fjord or a nearly isolated or silled basin with toxic bottom waters. Also, pertaining to the material (such as black organic sediments and hydrogen-sulfide muds) deposited in such an environment or basin, and to the process of deposition of such material (as in the Black Sea). Pertaining to a rock facies that includes black shales and graphitic sediments of various kinds. Etymol: Greek euxenos, hospitable.